Turbine engines, and particularly gas or combustion turbine engines, are rotary engines that extract energy from a flow of combusted gases passing through a fan with a plurality of blades, then into the engine through a series of compressor stages, which include pairs of rotating blades and stationary vanes, through a combustor, and then through a series of turbine stages, which include pairs of rotating blade and stationary vanes. In the compressor stages, the blades are supported by posts protruding from the rotor while the vanes are mounted to stator disks.
During operation air is pressurized in the compressor and mixed with fuel in the combustor for generating hot combustion gases which flow downstream through the turbine stages. Due to extreme temperatures of the combustion gas flow path and operating parameters, the stator vanes and rotating blades in both the turbine and compressor may become highly stressed with extreme mechanical and thermal loading. The vanes and blades, along with other engine components, must be able to handle these stresses. Composite airfoils are now commonly used for the vanes and blades to handle the thermal stresses while reducing weight for increased efficiency.
Additionally, composite airfoils can be formed to receive a metal leading edge element produced to reduce the effects of upstream gusts in airflow or foreign objects that occasionally pass by the airfoils. The airfoils must be able to withstand unsteady pressure and noise from the gusts along with an impact from the objects, especially the leading edge of the vane/blade.